Geek Answers Handbook

Android: detect if ListView has a scrollbar (after setting new data)

I have an ArrayAdapter associated with a ListView.

mListView.setAdapter(mArrayAdapter);

Whenever I reset ArrayList data in an ArrayAdapter:

mArrayAdapter.clear();
mArrayAdapter.addAll(mArrayList);
mArrayAdapter.notifyDataSetChanged()

ListView gets correct update

however, if right after the three lines above, I call my own method mListView.hasScrollbar()to determine if listview has a scrollbar or not, I get null lastVisibleItem:

public boolean hasScrollbar() {
    View lastVisibleItem = (View) getChildAt(getChildCount() - 1);
    if (lastVisibleItem.getBottom()>=getHeight()) {
        return true;
    }
    return false;
}

Does this mean that listview is still refreshing?

My main question is:
how can I check if the listview has a scroll bar after resetting the adapter with new data?

Thank you for your help!

+4
2

getLastVisiblePosition/getFirstVisiblePosition , ( getCount() ofc). , , , . , , , .

yourAdapter.notifyDataSetChanged();
yourAdapter.getListView().post(new Runnable() { 
    @Override public void run() { 
        //your code here        
    } 
});

notifySetDataChanged(), . , .

+2

, " , "?

, - listView.getFirstVisiblePosition() getLastVisiblePosition(), .

0

More articles:


All Articles